Help Me Pick the Right Drone Motor for My Patented Invention!

[CBF America]

Hello! I have recently received my patent for a unique, practical, and very effective personal cooling device I am calling the Cool body fan. I believe it would be best to utilize a drone propeller, motor, and battery, and have a variable speed knob as well. I am seeking references to exactly what parts may be best to use. The Constraints and attributes needed for the system are as follows:

---The propeller must be 6" to 7" in diameter.
---The more quiet the propeller is, the better.
---The more quiet the motor is, the better.
---Between the motor, propeller, and battery, I only need it to blow about as much air as the Ryobi fan (picture attached). 
---I would like a run time of at-least 4 hours on one charge.

I wont bother breaking down the design of the Cool Body Fan, but these attributes should be enough to go by.
Please feel free to provide any input or references that may be helpful. Ideally I'd like to find a specific part on the market for each component that people have recommended me and buy these for my third prototype.

Also, is it possible to simply wire a knob between a drone motor and battery to act as a speed dial? Let me know your thoughts.

Thank you very much!